The present invention relates generally to systems for automated or computer controlled assembly of cut material segments, such as segments cut from a sheet of limp material. More particularly, the invention relates to apparatus for picking up and transporting such cut material segments. By way of example, the invention may be used in the course of assembling cloth panels (cut segments) to form a garment, or it may be used in the course of resin transfer modling of articles, where for example graphite fiber woven panels (cut segments) are first cut, then placed in a mold and finally impregnated with an epoxy resin.
In the limp material automated assembly field, a cutting device, such as a laser, typically cuts individual material segments from a sheet of material and then a picking device extracts the cut segments and transports them to a staging area where they are assembled in a desired manner. The cutting device is typically controlled to cut several segments from a sheet in a manner which minimizes the amount of scrap material between the segments since such material is generally not usable. After the segments have been cut from a sheet, the picking device extracts the cut segments from the sheet, and preferably does so without disturbing the remaining cut segments and without disturbing the scrap. The picking device then transports the cut segments to the staging area and deposits them at predetermined locations.
Once a desired collection of cut segments have been precisely positioned at the staging area, they may be assembled together in various combinations, perhaps with other materials. One such type of assembled combination is commonly referred to as a "preform". The preforms may then be used to produce various products and articles.
Although cutting and sewing generally are old and well-known arts, there is a continuing need to develop improved systems for automated assembly, as well as to adapt to the special features of newly developed limp materials. Many of these new materials are lightweight and delicately woven, yet are tough and durable. Such materials may include synthetic materials used for example in outer-wear, or epoxy-graphite materials (commonly referred to as "composites") which are used in a variety of applications such as resin transfer molding processing, and in the production of goods such as sporting goods, radomes, and the like.
In the construction of composite parts by resin transfer molding processing, a preform is first assembled from material segments cut from a sheet of dry woven composite materials such as fiberglass or carbon fibers. The assembled preform is then placed in a mold and injected with resin to produce the finished part. Such preforms can be difficult and time consuming to make since they must be precisely assembled for quality control reasons, and since the composite materials used in their construction tend to be loosely woven and tend to distort and unravel at the slightest of handling thereby complicating the process of transporting the cut segments. There is therefore a need for improved systems for picking up and transporting segments which have been cut from a sheet of delicate, limp material, while maintaining the shape and integrity of the transported segments and also without disturbing other segments which may have been cut from the sheet and without disturbing the scrap.
The above-referenced U.S. patent application Ser. Nos. 08/027,098 and 08/325,484, and corresponding PCT International Application No. PCT/US94/00178 (International Publication No. WO 94/20399), which are hereby incorporated by reference, teach a method and an apparatus for handling cut material segments. However, there remains a need for improved inexpensive systems that can, in a highly repeatable manner, extract material segments which have been cut from a sheet of material without disturbing the sheet, and that can transport such segments without distorting their shape, and that can precisely deposit such segments at a desired location.
It is therefore an object of the present invention to provide an inexpensive segment pickup apparatus for the automated handling of limp material segments.
Other objects and advantages of the present invention will become apparent upon consideration of the appended drawings and description thereof.